You can easily use your grafic cards GPU which is up to 500 times more efficient! And the GPU often uses the same or even less power.

You can use your GPU to generate Bitcoins to support the Battleships Crossfire League by downloading and extracting this file. Just doubleclick the start.bat to begin donating. Every "Accepted" share has currently a value of 0.00002956 BTC. So with an average currency-value of 10 € and 100 accepted shares you donated about 0,03 € or 0,045 $.